000
FXUS62 KGSP 020516
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
116 AM EDT SUN AUG 2 2015
.SYNOPSIS...
DRY HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE AREA THROUGH THE
WEEKEND. LOW LEVEL MOISTURE WILL GRADUALLY RETURN NEXT WEEK AS
ANOTHER COLD FRONT APPROACHES FROM THE NORTH.
&&
.NEAR TERM /THROUGH TODAY/...
0515 UTC UPDATE...SKY OVER WAS UPDATED FROM INFRARED SATELLITE
IMAGERY. WINDS WERE UPDATED WITH THE LATEST NAM GUIDANCE. AREAS OF
MOUNTAIN FOG WERE UPDATED FORM THE LATEST LAMP GUIDANCE.
AS OF 1045 PM SATURDAY...LIGHT NORTHERLY FLOW CONTINUES TO WEAKEN
WITH LOSS OF SHALLOW MIXING LEADING TO A RATHER CALM/QUIET EVENING
ACROSS NORTHEAST GA AND THE WESTERN CAROLINAS. AS BEFORE...TWEAKED
TEMPERATURES AND DEWPOINTS TO BETTER ALIGN WITH RECENT OBS AND LEFT
THE REMAINDER OF THE FCST UNCHANGED AS IT WAS STILL ON TRACK.
PREVIOUS DISCUSSION...
AS OF 215 PM...NOT MUCH CHANGE IN THE UPPER PATTERN THRU THE NEAR
TERM...WITH A PERSISTENT TROF OVER THE EASTERN CONUS AND LARGE RIDGE
ACRS THE WEST. AN UNUSUALLY DRY AIR MASS FOR THIS TIME OF YEAR HAS
SETTLED IN ACRS THE AREA. THIS SHUD KEEP POPS AT A MINIMUM WITH JUST
A FEW CLOUDS HERE AND THERE. TEMPS WILL NEAR OR EVEN A DEG OR TWO
BELOW NORMAL IN SPOTS TONIGHT.
SUNDAY...MODELS HINT AT SOME RETURN OF LLVL MOISTURE INTO THE
AREA...AS SFC HIGH PRES BUILDS INTO THE CENTRAL
APPALACHIANS...ALLOWING FOR A LIGHT EASTERLY FLOW ATOP THE CWFA. THE
NAM IS MOST BULLISH ON THIS...AND HAS SOME CONVECTIVE RESPONSE IN
THE NC MTNS. THIS AND THE SREF ARE ABOUT THE ONLY MODELS THAT SHOW
THIS. I WILL KEEP A SLGT CHC POP FOR THE TYPICAL CENTRAL AND SW NC
MTN PEAKS THAT OFTEN STILL TRIGGER CONVECTION IN SPITE OF DRY
GUIDANCE. TEMPS WILL RISE TO A CATEGORY OR TWO ABOVE NORMAL AGAIN
WITH MOSTLY SUNNY SKIES EXPECTED.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
AS OF 215 PM SATURDAY...IT LOOKS LIKE OUR QUIET WEATHER WILL REMAIN
AT LEAST INTO MONDAY...THEREAFTER WE CAN EXPECT A RETURN TO MORE
DIURNAL THUNDERSTORM CHANCES AS LOW LEVEL MOISTURE STARTS TO
IMPROVE. THE DRY WEATHER CONTINUES ON SUNDAY NIGHT AND MONDAY AS WE
SHOULD STILL BE AT THE BOTTOM OF AN UPPER TROF WITH A WNW FLOW
ALOFT. DEWPOINT WILL PROBABLY MIX OUT AGAIN ON MONDAY AFTERNOON...
DOWN INTO THE 50S IN MANY PLACES E OF THE MTNS...WHICH WOULD CUT
BACK ON THE POTENTIAL FOR POSITIVE BUOYANCY. THE NAM ACTUALLY
DEVELOPS A MOISTURE BOUNDARY NEAR THE EASTERN FRINGE OF FCST AREA...
WHICH THE MODEL ACTS UPON WITH SHOWER DEVELOPMENT. FOR NOW...THIS
WAS DISCOUNTED AS BEING AN OUTLIER. THE FCST WAS KEPT DRY OVER THE
PIEDMONT...THRU TUESDAY MORNING. SOME CHANGES WILL BEGIN ON TUESDAY
AS A SHORT WAVE TO THE WEST BEGINS TO FLATTEN AND LIFT THE TROF.
THIS ALLOWS MOISTURE TO INCREASE AS A SURFACE BOUNDARY STARTS TO SAG
DOWN INTO THE REGION FROM THE N. THE INCREASED BUOYANCY COMBINED
WITH THE POTENTIAL TRIGGER SUGGESTS A BETTER CHC FOR AFTERNOON
STORMS...AT LEAST OVER THE NC PART OF THE FCST AREA...SO PRECIP
CHANCES WERE NUDGED A BIT ABOVE GUIDANCE. TEMPS WILL CLIMB A BIT
EACH DAY...BUT RH WILL BE LOW ENOUGH SO AS TO KEEP HEAT INDEX BELOW
ADVISORY CRITERIA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
WEDNESDAY WITH BROAD UPPER TROFFING CENTERED OVER THE GREAT LAKES
AND PERSISTENT UPPER RIDGING OVER THE WESTERN CONUS. OVER THE NEXT
COUPLE OF DAYS...THE PATTERN IS EXPECTED TO DEAMPLIFY TO SOME DEGREE
AS THE UPPER TROF LIFTS TO THE NE AND ANOTHER NORTHERN STREAM UPPER
TROF HELPS TO FLATTEN THE RIDGE OVER THE WEST. AT THE SAME TIME...A
SERIES OF FAIRLY POTENT LOOKING EMBEDDED UPPER SHORTWAVES APPROACH
THE FCST AREA FROM THE WEST AND NW. AT THE SFC...THE SUBTROPICAL
BERMUDA HIGH WILL MAINTAIN ITS INFLUENCE OVER THE SE REGION THRU
MOST OF THE PERIOD WITH GENERALLY LIGHT SLY FLOW. AS HAS BEEN THE
CASE OVER THE PAST COUPLE OF WEEKS...THE LONG RANGE MODELS DO NOT
APPEAR VERY CONSISTENT WITH THE EVOLUTION OF THE SFC PATTERN FOR
MOST OF THE MEDIUM RANGE. THEY ATTEMPT TO SPIN UP SOME SORT OF LOW
ON THRUS AND MOVE IT OFFSHORE BY FRI AND THEN DEVELOP ANOTHER LOW
JUST TO OUR WEST ON FRI AND END WITH DRIER CONDITIONS FOR SAT. AT
THIS POINT...IT IS DIFFICULT TO PLACE MUCH CONFIDENCE ON ANY
SPECIFIC MODEL SOLUTION SO I OPTED FOR AN OVERALL BLEND. POPS
INCREASE FOR THURS AND FRI AND TAPER BACK AGAIN ON SAT BUT STILL
REMAIN AT SLIGHT TO SOLID CHANCE. TEMPS START OUT ABOVE NORMAL AND
THEN COOL A FEW DEGREES TOWARDS THE END OF THE WEEK.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AT KCLT...VFR. A RELATIVELY DRY AIR MASS NORTH OF A COASTAL FRONT
WILL NOT SUPPORT RESTRICTIONS...ALTHOUGH MODEL TIME HEIGHTS SHOW
LIMITED CLOUD COVER AT AROUND 6000 FT...WITH THE BEST COVERAGE
BEFORE MID MORNING. LIGHT WINDS WILL FAVOR THE NE UNTIL THIS
EVENING...WHEN THEY VEER SW.
ELSEWHERE...VFR. SEVERAL GUIDANCE MEMBERS SUPPORT DAYBREAK
FOG...MAINLY IN THE NC MOUNTAINS. WITH LIMITED CONFIDENCE AND A
RELATIVELY DRY AIR MASS...VFR WILL BE CARRIED AT KAVL PER THE LAMP
GUIDANCE. LOW VFR CIGS WILL LIKELY BE LIMITED TO PORTIONS OF THE NC
MOUNTAINS WHERE CONVECTION WILL BE POSSIBLE THIS AFTERNOON. WINDS
WILL VEER FROM N TO NE THIS MORNING...EXCEPT AT KAVL WHERE THEY WILL
VEER SE TODAY AND RETURN TO N TONIGHT.
OUTLOOK...FLIGHT CONDITIONS WILL REMAIN RESTRICTION FREE THROUGH THE
WEEKEND AHEAD OF GRADUALLY INCREASING PRECIPITATION/RESTRICTION
CHANCES THROUGH MID WEEK AS MOIST SOUTHERLY FLOW RETURNS.
CONFIDENCE TABLE...
04-10Z 10-16Z 16-22Z 22-00Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...ARK/CDG/JAT
SHORT TERM...PM
LONG TERM...JPT
AVIATION...JAT